1. Technical Field
The present invention relates to an image display apparatus of an active matrix type, and more specifically relates to an active matrix circuit, a method of manufacturing the active matrix circuit and an image display apparatus.
2. Description of Related Art
As a liquid crystal panel used in an image display apparatus, there is a liquid crystal panel comprising an active matrix circuit. In the active matrix circuit, a plurality of pixel electrodes which apply a voltage to liquid crystal corresponding to pixels are arranged in a matrix, and an active element is connected to each of the pixel electrodes. The active element is a TFT (thin film transistor), for example. In the active matrix circuit, a plurality of parallel signal wires and a plurality of other signal wires which are orthogonal to said plurality of signal wires are arranged, and the active element is connected to two signal wires which cross each other in a plan view. A current flows through the two crossing signal wires, thereby the active element is turned on and the pixel electrode applies a voltage to the liquid crystal to drive the liquid crystal panel.
The active matrix circuit often comprises a protection circuit which protects the active element from static electricity. Japanese Patent Application Laid-Open No. H10-20336 discloses an example of an active matrix circuit comprising a protection circuit. In the protection circuit disclosed in Japanese Patent Application Laid-Open No. H10-20336, two switching elements are connected between two adjacent signal wires in anti-parallel. In a case where deviation of charges arises between the two adjacent signal wires due to static electricity, the switching element of the protection circuit is turned on, and the charges are distributed to the plurality of signal wires to protect the active element which operates the pixel electrode. In a case where the deviation of charges does not arise, the switching element of the protection circuit is in an off-state, a resistance between the two adjacent signal wires is high, and no effect is exercised on a signal traveling through the signal wires.